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Zika Virus

A virus that has only recently been widely reported in the media

Although the media have covered the Zika virus subject only recently, its discovery is not recent, contrary to what one might think. In fact in 1947 the presence of this virus is detected in a monkey in the Zika forest (from where it takes its name). A year later in 1948 the Zika virus is detected in a tiger mosquito (also called Aedes). Its transmission to humans is officially confirmed and recognized in 1954 in Africa, the African continent is considered the cradle of the virus. It is only in 2007 that an epidemic we had to deal with occurred in Yap Islands in Micronesia. Mainly confined to tropical regions of Africa and Asia in the first instance, the virus has since spread especially in America but also in Europe. A relative panic settled in the minds of many travelers, which should lead to multiple precaution and prevention measures against this virus. These fears are perfectly understandable when one considers that the method of propagation is unfortunately of a terrifying simplicity. In fact a simple mosquito bite is enough to contract this disease.

The tiger mosquito as the main contamination vector

The Zika virus is part of what is called arboviruses, i.e. a virus transmitted by insects, a virus part of the Flavivirus, Flaviviridae family, where we can list the dengue virus, the yellow fever virus but also the infamous chikungunya virus, among many others. The Zika virus is mainly transmitted by the tiger mosquito, a type of very aggressive mosquito and easily recognizable by its physiological feature namely the presence of black and white stripes on the body and paws; the tiger mosquito is also responsible for the transmission of many of other diseases. The method of spreading explains the extend of the disease on the planetary scale. In fact, the mosquito is carrying the virus when it bites an infected patient. The mosquito carrying the Zika virus becomes itself the live and “volatile” vector of a massive contamination which explains the geographically rapid spread of the virus. We have even witnessed a transmission in some cases (even if rare) of Human to Human virus without exterior vector, during sexual intercourse but also during birth. One can even extrapolate to contamination by contact with saliva or urine as this virus has been found in the biological fluids of infected persons.

The symptoms of Zika virus

After an incubation period of 3 to 12 days being contaminated  with the mosquito bite, symptoms occur in about 20% of patients infected which means that nearly 80% of people bitten by an infected mosquito do not notice anything. Further, it is often very difficult to make a diagnosis because the clinical symptoms are strongly similar with viruses such as dengue and yellow fever. You can list these symptoms that may be characterized as mild fever (higher or lower) (from where it takes its name of Zika fever), rash, headaches, conjunctivitis, edema, muscle and joint pain, digestive disorders … these disorders subside again in most cases in about a week. The virus remains a virus that does not require special medical supervision.

Rare but serious complications

If the symptoms disappear in most patients, the complications that can occur must not be minimized. In fact, one can distinguish two main complications. There is evidence of severe neurological damage in some patients leading to a paralysis of the lower limbs. It’s called the Guillain-Barre syndrome, an ascending paralysis that goes back to the chest, in the most severe cases, being impossible for the patient to breathe, thus requiring intensive care. The most serious complication affects pregnant women infected during pregnancy, the fetus (and stem cells giving rise to the brain) then being also affected by the virus in an intrauterine way. The consequences are catastrophic with cases of microcephaly in the newborn (malformation of the skull which proves smaller than normal), the brain development (the motor development) of the child being then irreversibly damaged.

Am I infected? What tests should I do?

Have you returned from a trip in a risk area? Do you have doubts after the occurrence of one or more symptom which I have listed? The blood test (ELISA enzyme immunoassay or search by RT-PCR), urine or saliva samples are the only reliable ways to know if you are infected or not. Contact us for more information.

Existing treatments

Unfortunately there is no antiviral treatment, much less a vaccine against the Zika virus. Therefore  we can only treat symptoms by taking analgesics. Your doctor will be the only one entitled to determine an order for taking these drugs as some known interactions have been observed (e.g. bleeding and aspirin taking) self-medication is therefore to be avoided! Note however that research is ongoing; antibodies have been discovered, these neutralizing both the Zika virus and the dengue virus (both viruses having much in common). If tests on mice are promising, the hope for a human vaccine depends on the future human trials. Prevention and common sense Avoiding infection by Zika virus means avoiding mosquito bites, there is no other means. To avoid the consequences the cause must be treated in endemic areas. The spread of the virus being rapid and uncontrolled, common sense tips are to be followed all over the world where heat and humidity factors are combined, two factors necessary for the occurrence of mosquitoes. The tiger mosquito likes stagnant water which then becomes a perfect area for the growth of the larvae. The gardens must be screened to get rid of all potential foci: flower pots, poorly-maintained gutters … It goes without saying that all travelers must be very cautious. They will think to take in their luggage loose, long clothing, mosquito nets, repellents, insecticides … in order to protect during the night but also during the day. Unprotected sex is of course avoided in endemic areas. Women, especially in areas at risk, are recommended to defer any birth plan and to speak to their doctor.